Papers by Keyword: Nonstoichiometric

Abstract: Bi_0.9Ba_0.1Fe_0.95O₃ and Bi_0.9Ba_0.1Fe_xTi_0.05O₃ (x=0.95, 0.925, 0.90) ceramics were prepared through conventional solid state reactions. X-ray diffraction analyses indicated that a high content of perovskite phase was obtained for all the four compositions. While the three (Ba,Ti)-codoped compositions all showed a higher resistivity than Bi_0.9Ba_0.1Fe_0.95O₃, and Bi_0.9Ba_0.1Fe_0.925Ti_0.05O₃ had the best electrical and dielectric properties among the three (Ba,Ti)-codoped compositions, including the largest dielectric constant, the smallest dielectric loss at low frequency range, and the highest electrical resistivity. Magnetic hysteresis loop measurement revealed that the four compositions had similarly enhanced magnetic properties. It is concluded that much attention should be paid to fine composition adjustment when multiple elements are co-doped to BiFeO₃ system.

Abstract: Nonstoichiometric Zinc oxide (ZnO) nanorod arrays doped Co or Ni can be easily obtained by calicining soaked ZnO nanorod arrays. More importantly, the nonstoichiometric doped ZnO nanoarrays have more effective antimicrobial than pure ZnO nanoarrays, which means we can obtain a kind of promising new effective functional nanomaterials.

Abstract: Lithium iron phosphate with varied Fe/P molar ratio was synthesized from LiOH, FeSO₄, and H₃PO₄ by hydrothermal route at 180°C for 6 h. The samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), chemical analysis, and constant current charge-discharge cycling test. It was found that at the same pH value of reaction, the Fe/P ratio had a major effect on the content of impurity phase, crystal structure and electrochemical performance of the samples. However, it had a minor effect on the morphology of the samples. A single phase structure was obtained for the samples with the Fe/P ratio of 0.97-1.02. The sample with the Fe/P ratio of 0.97 exhibited the best electrochemical behaviors, whose specific discharge capacities could reach 152.7, 144.8 and 133.2mAhg^-1 at 0.2C, 1C and 5C rate, respectively, with the capacity retention rate close to 100% after 50 cycles at 5C. It is believed that the excellent electrochemical performance of specific discharge capacity, rate capability and cycling stability is attributed to the nonstoichiometry of LiFePO₄, which results in the Li-rich defective crystal structure and the decrease of cell parameters, thus facilitating the discharge behaviors at high rates.